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T O P I C R E V I E W

Robert Pearlman

NASA release

NASA Preparing for DM-2 Test: Now That's Powerful Information

Preparations are under way for the testing of NASA's next generation, five-segment solid rocket development motor — DM-2 — in September. The test is designed to advance the understanding, safety, technology and capability of solid rocket motors.

The five-segment DM-2 motor — capable of producing 22 million horsepower and generating as much as 3.6 million pounds of thrust — was developed by ATK Space Systems, a division of Alliant Techsystems of Brigham City, Utah, the prime contractor for the solid rocket motor, and is being assembled at ATK's test stand in Promontory, Utah. This will be the second, full-scale, full-duration test of the new development motor, which follows the successful test of DM-1 last fall.

"The successful DM-1 test provided our team with great results," said Andy Schorr, first stage, five-segment motor lead for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Ala. "All performance measurements were within specified limits and 46 total objectives, covering each significant design feature of the motor, were met.

During this "cold motor" test, DM-2's overall temperature will be lowered to 40 degrees Fahrenheit to validate the motor's performance in cold weather. This is in contrast to the DM-1 test firing which was conducted at ambient temperature. As the test is conducted, technicians will collect data from 759 sensors to assess the motor's performance and validate motor enhancements. Measurements gathered will be used to evaluate thrust, roll control, acoustics, motor vibrations, nozzle modifications and insulation upgrades.

Although similar to the solid rocket boosters that help power the space shuttle to orbit, DM-2 includes several upgrades and technology improvements, including the addition of a fifth segment, a modified nozzle throat and upgraded insulated liner. With these changes, engineers hope to improve performance and provide greater safety and reliability for NASA's next-generation launch vehicle.

"Our team is responsible for developing a robust propulsion system that can provide the thrust necessary to escape Earth's gravitational well and safely deliver astronaut crews and payloads to the International Space Station and beyond," Schorr said. "As we press forward, our goal is to optimize every aspect of the system for peak performance."

Large, solid rocket motors have been a primary propulsion element in modern space exploration — used as booster motors for the space shuttle, Atlas V and Delta IV rockets and several military applications. They provide high thrust, or lifting power, for relatively low cost, and do not have the more costly refrigeration and insulation requirements of cryogenic liquid-fueled rockets.

A development test motor is used to simulate conditions experienced in flight. It offers engineers an opportunity to better assess the strength of the motor's current design, spot any flaws in the new designs, verify new materials and certify manufacturing processes.

"Tests such as DM-2 allow our team to improve and enhance existing technology essential to maintaining America's preeminence in space, even as we look to new designs, new materials and new technologies with the potential to transform the future of human spaceflight," he said.

Engineers and technicians at Alliant Techsystems (NYSE: ATK) and NASA have completed installation work on the second Ares I First Stage five-segment Development Motor (DM-2), in preparation for its static-fire, which is currently scheduled for early September.

The Ares I First Stage is the largest solid rocket motor ever built. It was designed to maximize astronaut safety while providing the nation with a reliable launch capability for both crew and cargo missions. As the prime contractor, ATK continues to perform on schedule and cost in support of NASA's space exploration programs.

The motor, which is 154 feet in length and 12 feet in diameter, has been installed horizontally in a specialized test stand in Utah. Results from this test will be compared with data from the ground test of the first five-segment motor and Ares I-X test flight both successfully completed last year.

"A robust ground and flight test program is a critical part of human-rating to ensure reliability and safety when launching crew into any orbit," said Charlie Precourt, VP and GM of ATK Space Launch Systems. "This test is a vital milestone in further growing the performance database for this new five-segment solid rocket motor."

Although the five-segment motor is based on the design heritage of the flight-proven Solid Rocket Boosters on the Space Shuttle Program, it was upgraded utilizing modern technologies and materials. These include the addition of a fifth segment, changes to the propellant grain, a larger nozzle opening and upgraded insulation and liner.

"We designed this motor using a knowledge base gained from over three decades of operations, during which we constantly monitored and improved our design," said Precourt.

ATK technicians are in the process of instrumenting the five-segment rocket with sensors and gages to collect measurements on more than 750 data channels. This information will be used to evaluate performance, roll control, acoustics, motor vibrations, oscillations, nozzle modifications and insulation upgrades. The full-scale motor test will advance the safety, technology and knowledge of solid rocket motors.

When fired, the motor will produce 3.6 million pounds of maximum thrust or 22 million horsepower. Utilizing the in-line configuration with a single five-segment solid rocket motor first stage and liquid upper stage, this launch vehicle is designed to lift more than 54,000 pounds of payload directly to Low Earth Orbit.

"The combination of a solid propulsion first stage and liquid propulsion upper stage provides optimum payload capability, reliability and lowest cost," said Precourt. "These motors were designed not only to carry humans to orbit but also for use on a heavy lift vehicle where performance and reliability are key requirements."

Provide side load data that can be used in future test flights leading to heavy lift development.

Compare roll torque data to information collected from the stable flight of Ares I-X to further the design of the roll control system.

The first stage is designed to be recovered and reused. This enables NASA and ATK to collect vital post-flight information and performance data, confirming a safe and robust design.

Robert Pearlman

Alliant Techsystems (ATK) release

ATK and NASA to Perform Second Ground Test of the Ares Five-Segment Solid Rocket Motor

Alliant Techsystems and NASA will test the second fully developed Ares I five-segment solid rocket motor, known as Development Motor-2 (DM-2). The five-segment rocket motor is an upgraded version of the Shuttle's 4-segment booster, and has also been identified as a key element of NASA's future Heavy Lift Launch vehicle.

What: Horizontal ground test firing of Ares I first stage

Date: Tuesday August 31, 2010

Time: 9:05 a.m. MDT

Where: ATK Aerospace Systems facility in Promontory, Utah

Test Objectives/Background:

A total of 53 design objectives will be measured through more than 760 instruments.

DM-2 is a "cold motor" test. The motor will be cooled to 40*F to measure solid rocket motor performance at low temperature, as well as to verify design requirements of new materials in the motor joints. These new materials will allow for the elimination of joint heaters that were necessary in the original 4-segment motor design. This will save significant weight, further reduce system complexity and simplify launch operations, while simultaneously delivering increased operating margins at lower ambient temperatures.

Other objectives include data gathering on vital motor upgrades such as the new insulation and motor case liner and the redesigned nozzle which increase the robustness of the design.

When fired, the motor will produce a maximum thrust 3.6 million pounds, or 22 million horse power.

The cases have all previously flown on the space shuttle, collectively launching on 57 missions.

A public viewing area is available along State Road 83 North approximately 20 miles west of Corinne, Utah.

The static firing of the solid motor, designated Development Motor-2, will last two minutes. This is the most heavily instrumented solid rocket motor in NASA history, with 53 test objectives that will be measured using more than 760 instruments. The motor was built as an element of NASA's Constellation Program. It is the largest and most powerful solid rocket motor designed for flight and is highly transferable to future heavy-lift vehicle designs.

NASA Television's live coverage of the test will begin at 11:20 a.m. EDT and will broadcast a news conference at 12:30 p.m. EDT with representatives from NASA and ATK.

The motor design is almost identical to another development motor tested last year. However, DM-2 will be cooled to 40 degrees Fahrenheit for this full-duration firing to verify the performance of new materials. After more testing, the first-stage solid rocket motor will be certified to fly at temperature ranges between 40-90 degrees Fahrenheit.

ATK and NASA Successfully Test the Second Five-Segment Ares Development Motor (DM-2)

Alliant Techsystems and NASA conducted a successful ground test earlier today of the second Ares five-segment Development Motor (DM-2). The successful test is an important milestone in the development of America's next generation of launch vehicles.

Initial test data indicated that the motor, which was chilled to a 40° F core temperature since early July, performed as designed, producing approximately 3.6 million pounds of thrust, or 22 million horsepower, and burned for just over two minutes. The test collected 764 channels of data to accomplish 53 test objectives. This is the most data ATK has ever collected in a static fire test.

"The information collected from this test, used together with data from DM-1 and the Ares I-X flight test, will help further validate the five-segment design leading to critical design review next year," said Charlie Precourt, vice president and general manger, ATK Aerospace Systems, Space Launch Systems. "The data will also confirm the performance and reliability of this solid rocket, which can be configured for use on multiple launch vehicles."

The five-segment rocket was designed to maximize astronaut safety while providing the United States with an affordable and reliable launch capability for both crew and cargo missions. For example, a single five-segment solid rocket motor first stage, coupled with a liquid upper stage, would be able to lift more than 55,000 pounds of payload directly to Low Earth Orbit.

The main test objectives from today's static motor firing were measuring the first-stage rocket's performance at cold temperatures, and verifying the performance of new materials in the motor joints at the lowest range of operational temperatures.

"Testing at these extremes aids us in fully understanding all operating conditions for this motor," said Precourt, a former shuttle astronaut. "This data, along with information we have collected over the past three decades, confirms that this is the most powerful and reliable solid rocket motor ever designed, and it is the right motor to ensure the safety of our astronauts."

DM-2 is the largest human-rated solid rocket motor built today, measuring 12 feet in diameter and 154 feet in length. The five-segment motor is based on the design heritage of the flight-proven Solid Rocket Boosters on the Space Shuttle Program, and has been upgraded to incorporate modern technologies and materials. These include the addition of a fifth segment, changes to the propellant grain, a larger nozzle opening and upgraded insulation and liner.

The five-segment cases remain the same as those used for more than three decades on the Space Shuttle Program. Just like shuttle cases, the cases for this rocket are designed to be recovered and reused. This enables NASA and ATK to collect vital post-flight information and performance data, confirming a safe and robust design. The cases used in this ground test have collectively flown on 59 previous shuttle missions.

As the prime contractor, ATK continues to perform on schedule and on cost in support of NASA's space exploration programs. The next test for the program, Development Motor-3, will be a hot temperature test conducted next year.

Robert Pearlman

NASA release

NASA and ATK Successfully Test Five-Segment Solid Rocket Motor

With a loud roar and mighty column of flame, NASA and ATK Aerospace Systems successfully completed a two-minute, full-scale test of the largest and most powerful solid rocket motor designed for flight. The motor is potentially transferable to future heavy-lift launch vehicle designs.

The stationary firing of the first-stage development solid rocket motor, dubbed DM-2, was the most heavily instrumented solid rocket motor test in NASA history. More than 760 instruments measured 53 test objectives.

Prior to the static test, the solid rocket motor was cooled to 40 degrees Fahrenheit to verify the performance of new materials and assess motor performance at low temperatures during the full-duration test. Initial test data showed the motor performance met all expectations.

"For every few degrees the temperature rises, solid propellant burns slightly faster and only through robust ground testing can we understand how material and motor performance is impacted by different operating conditions," said Alex Priskos, first stage manager for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Ala. "Ground-testing at temperature extremes pushes this system to its limits, which advances our understanding of five-segment solid rocket motor performance."

The first-stage solid rocket motor is designed to generate up to 3.6-million pounds of thrust at launch. Information collected from this test, together with data from the first development motor test last year, will be evaluated to better understand the performance and reliability of the design.

Although similar to the solid rocket boosters that help power the space shuttle to orbit, the five-segment development motor includes several upgrades and technology improvements implemented by NASA and ATK engineers. Motor upgrades from a shuttle booster include the addition of a fifth segment, a larger nozzle throat, and upgraded insulation and liner. The motor cases are flight-proven hardware used on shuttle launches for more than three decades. The cases used in this ground test have collectively launched 59 previous missions, the earliest being STS-3.

After more testing, the first-stage solid rocket motor will be certified to fly at temperature ranges between 40-90 degrees Fahrenheit. The solid rocket motor was built as an element of NASA's Constellation Program and is managed by the Ares Projects Office at Marshall. ATK Aerospace Systems, a division of Alliant Techsystems of Brigham City, Utah, is the prime contractor.